1. Field of the Invention
This invention is concerned with a tool for setting two-part fasteners of the kind in which one part requires to be pushed and the other pulled to set the fastener, comprising a housing, a thrust member reciprocable back and forth along an axis of the housing and having a fastener-engaging face at its forward end to push on said one part of the fastener in a fastener-setting operation, and pulling means also reciprocable within the housing along said axis to pull the other part of the fastener relative to the thrust member in the fastener-setting operation.
2. Summary of the Prior Art
Tools for setting two-part fasteners, for example blind-riveting assemblies and lockbolts, are known which comprise a housing in which there are arranged to reciprocate along a common axis a thrust member to push against a head of the rivet of a blind-riveting assembly or the collar of a lockbolt and pulling means arranged to pull the mandrel of the former or the bolt of the latter, as the case may be. It is also known to effect the strokes of the thrust member and pulling means by fluid pressure. Furthermore, in U.S. Pat. No. 3,996,784, which describes in particular a lockbolt-setting tool, there is disclosed an arrangement in which the thrust member is constituted by a sleeve with a piston at its rear end, and the pulling means also comprises a sleeve, largely accommodated in that of the thrust member, and also with a piston at its rear end, the two pistons operating in the same fluid pressure cylinder, that of the pulling means behind that of the thrust member. Ports are provided in the cylinder to admit fluid under pressure at each end and at an intermediate position along the cylinder wall. Thus, operative strokes of the thrust member and pulling means can be effected by valve means controlling the flow of fluid through the said ports of the single cylinder. Some degree of independence of movement of the thrust member and pulling means is thus afforded in a simple and economic construction of tool, but such independence of movement is limited by the position of the port part way along the cylinder, the stroke of the thrust member being restricted to the part of the cylinder in front of this port and that of the pulling means to the part of the cylinder behind it.